Classic examples of paralyzed extraocular muscle are congenital or acquired complete third nerve palsy and ocular fibrosis syndrome. An ophthalmic complication encountered with increasing frequency in functional endoscopic sinus surgery (FESS) is inadvertent amputation of the medial rectus muscle. The consequence of such medial rectus dysfunction is that the involved eye assumes a large angle exotropia, an inability to adduct the eye, and disabling diplopia. Occasionally, severe paralytic and restrictive or absent extraocular muscle will require globe fixation in the primary position because of the presence of an active antagonist muscle.
Surgical remedies include supramaximal recession of the lateral rectus and transposition of the vertical muscles to replace the lost motor function of the transected medial rectus, or passively fixating the globe to the periosteum of the medial wall. Unfortunately, operating on the remaining three rectus muscles could compromise the blood supply to the eye, leading to anterior segment ischemia and reduced visual acuity. Attaching the eye to the medial wall periosteum fixates the globe into one primary position permanently, rendering it unable to abduct and thus negating the effect of the normal functioning lateral rectus muscle. Permanent suture material and autogenous fascia such as temporalis fascia attached to the remnant of the transected muscle have been attempted. Use of the apically based periosteal flap to tether the globe in primary position has been advocated. (Goldberg R A, Rosenbaum A L, Tong J T; “Use of apically based periosteal flaps as globe tethers in severe paretic strabismus”; Arch Opthalmol 2000; 118; 431-437). All these surgical options share one major drawback—the globe is tethered to one position, unable to adduct or abduct the eye. Scott and Associates (Scott A B, Miller J M, Collins C C; “Eye Muscle Prosthesis”; J Pediatr Opthalmol Strabismus, 1992; 29:216-218) inserted a silicone rubber band along the course of the paralyzed muscle to restore alignment and to provide an elastic band against which the antagonist could pull. In their cases, there was a reduction in motility in the first or second month following surgery. The authors attributed the reduced motility to the development of a fibrous membrane surrounding the implant which acts as a further restriction to the antagonist. Bicas (Bicas HEA, “A surgically implanted elastic band to restore paralyzed ocular rotations”; J Pediatr Ophthalmol Strabismus. 1991; 28:10-13) placed a doubled 1-millimeter silicone tubing from the front of the globe to the orbit. This is an improvement over purely holding the eye to the orbital periosteum with sutures, as the implanted elastic band provides a posteriorly directed vector.